GEMINI MAN

       Sam Casey, the Gemini Man, is an agent with INTERSECT.
       I have seen that organization's name spelled with all caps and with the normal proper case so am not sure which is correct.
       However it is capitalized, it stands for "International Security Techniques" and is billed as a "high-tech government think tank" though as far as I know, think tanks do not routinely employ highly skilled operatives to go on secret missions to fight international bad guys and the like. Which leads to the belief that the think tank, while certainly legitimate, is also a cover for a clandestine intelligence group.
       Casey is one of this agency's best agents though he hardly looks the part of an operative, prone as he is to wearing jeans and riding a motorcycle and overall appearing to be a bit of a rebel. We will learn very little about Casey's past in the dozen of adventures we have of him so we do not know how long he had worked for INTERSECT prior to the incident that brought him to our attention, but it must have been a few years because he is very much respected there.
       The incident in question occurred on a mission to find and retrieve a Soviet spy satellite which had fallen to Earth and landed in the ocean. It was Casey's job to scuba-dive to get it. What else was in the satellite to make it explode I do not know but that explosion unleashed some chemicals which changed the makeup of Casey's body as he was caught in the mix. The result of which is that Casey was rendered invisible.
       INTERSECT's chief scientist, Dr. Abby Lawrence, found a way to temporarily counteract the invisibility with the help of her "DNA stabilizer". This small device was built into a watch which Casey wears and which he can push a button to turn off the stabilization thus turning him invisible again.
       Confusing parts here:
       1) When Casey pushes that button, he turns invisible. So do whatever clothes he happens to be wearing. How? Maybe he exudes a sort of forcefield.
       2) He can only stay invisible for 15 minutes per day or he risks dying. But he was invisible from the time of the explosion to likely days or weeks later when Dr. Lawrence came up with the stabilizer. How? Maybe once he was stabilized, the problem arose.
       Whatever the answers to these questions, Casey had one heckuva gift for a secret agent.

       I do not rate this television series very high because it really, in my mind, knocked off David McCallum's The Invisible Man series and because there was so little of it for me to see back in the day. Plus I did not care that much for the lead actor. So when you get down to it, I was predisposed against it and decades later, I obviously remain so.
       Now, I did like Dr. Abby Lawrence but being male at the time, well, who wouldn't like the lovely and smart doctor. The illogic of some of the premise still annoy today but my appreciation for the doctor remains.